Low friction plastic weatherstrip

ABSTRACT

A co-extruded all-polymer weatherstrip has a retainer including a base portion and support portion, an elastic portion extending upwardly from the retainer for providing the desired and needed resiliency, and a generally rigid contact strip supported by and integral with the elastic portion. The rigid contact strip is self-supporting so as to retain its shape and position without becoming creased, wrinkled or bunched-up when subjected to sliding action.

FIELD OF THE INVENTION

The present invention relates to the sealing of doors, windows and thelike; and more particularly, the invention relates to an improved lowfriction plastic weatherstrip material.

BACKGROUND OF THE INVENTION

Many types of weatherstrip material exist, and a great variety ofdifferent types of weatherstrip materials have been provided in thepast. Also, the patent literature is replete with different types ofweatherstrip among which may be mentioned the Schlagel et al U.S. Pat.No. 2,228,368; Spraragen U.S. Pat. No. 2,232,570; Balfe U.S. Pat. No.2,336,835; Merrill U.S. Pat. No. 2,475,332 and Olson U.S. Pat. No.4,064,654. Of these, the Olson U.S. Pat. No. '654 is of the general typeespecially constructed for slidable closures, retained in a confiningchannel in one element with a contact surface projecting therefrom forsliding engagement with a second element.

The Gerald Kessler U.S. Pat. Nos. 3,535,824 and 3,685,206 disclose lowfriction abrasion resistant plastic weatherstrips of the same generaltype. More recently, all-plastic weatherstrips have appeared on themarket having a rigid base and a flexible generally cylindrical sealingportion projecting therefrom, in some cases the upper surface of thesealing portion being coated with a low friction material. The upwardlyprojecting sealing portion is generally configured as a circularcylinder and may be either hollow or filled, such as with spongematerial. While the circular cylindrical configuration provides a goodsealing function and the low friction coating when present provides theadvantages of the aforementioned Kessler patents, these newconstructions suffer from a serious disadvantage.

Thus, even those new constructions which are provided with a lowfriction coating have a tendency to crease, "gather" or bunch-up when amating surface is moved longitudinally thereagainst, e.g. when aweatherstripping material of this type is used in a horizontal sliderwindow or a patio door or the like. As a result, the sealing efficiencyof the weatherstrip material becomes reduced and, moreover, frictionincreases and it becomes increasingly difficult to slide open the windowor door.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to overcomedeficiencies in the prior art, such as indicated above.

It is another object to provide for improved weather sealing betweenelements which slide relative to one another.

It is a further object of the invention to provide an improvedweatherstrip material particularly adapted for use in a slidingenvironment.

It is still another object of the present invention to provide aweatherstrip material which has a rigid, relatively low friction contactsurface which will slide easily and will not bunch-up or crinkle orcrease or gather when it is moved longitudinally such as in a horizontalslider window or a patio door.

These and other objects and the nature and advantages of the instantinvention will be more apparent from the following detailed descriptionof certain illustrated embodiments taken in conjunction with the drawingbelow. In general, however, the improved weatherstrip of the presentinvention is provided with a contact surface which is rigid and which issupported therebeneath by elastic supports. The contact surface can beof any desired configuration such as rounded, smooth, ribbed or even afin, the main point being that it is rigid and will slide and will notbunch-up when it is moved longitudinally such as in a horizontal sliderwindow or patio door.

BRIEF DESCRIPTION OF DRAWING

FIGS. 1-9 are cross-sectional views of different embodiments of anextruded all-plastic weatherstrip according to the invention; and

FIG. 10 is a cross-sectional view of another embodiment in a typical useenvironment.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 shows a first weatherstrip 10 having a bottom retainer sectioncomprising a longitudinally extending base portion 12 and alongitudinally extending support portion 14 projecting upwardly from thebase portion 12 and integral and unitary therewith. The base portion 12and support portion 14 are both sufficiently rigid and strong so as tobe capable of retaining their shape and position when the weatherstripis subjected to pressure from the surface to be sealed. It will beunderstood that the retainer can be of any shape, and its configurationis designed for its intended environment of use. While it must besufficiently strong and rigid to retain its shape and position asindicated above when captured in a supporting structure, considerableflexibility may be possible depending on the circumstances.

Projecting upwardly from the support portion 14 and integral therewithis an elastic portion 16 which may be formed of an elastomer or aresilient plastic. It is the elastic portion 16 which provides theweatherstrip 10 with its ability to resiliently contact a surfaceagainst which the weatherstrip 10 will slide, thereby effecting itssealing function, and yet be capable of accommodating different sizes ofgaps between the sliding members due to inevitable manufacturingtolerances. While the elastic portion 16 may be not unitary with theretainer 12, 14, it is integrally connected therewith.

Supported by the elastic portion 16 is a self-supporting, longitudinallyextending contact strip 18 which directly contacts the surface to besealed. The contact strip 18 extends transversely and defines the widthof the weatherstrip 10. It is important according to the invention thatthe contact strip 18 be sufficiently rigid to substantially retain itsshape and position when the weatherstrip 10 is subjected to pressurefrom the surface to be sealed, i.e. the contact strip must besufficiently rigid so as not to gather, crease or wrinkle bunch-up whenit is moved longitudinally relative to the surface to be sealed.Desirably, the contact strip 18 is formed of a low friction plastic suchas polyethylene or polypropylene. Since the contact strip 18 is rigidwhile the elastic portion 16 is more flexible, these elements willnormally not be unitary, i.e. not made of the same material, althoughthey are integrally connected.

While in FIG. 1 the contact strip 18 of the weatherstrip 10 is shown asbeing generally planar, it can take a variety of configurations such asrounded, smooth or ribbed. Thus, in FIG. 2 there is shown a variation 20wherein the contact strip 28 is rounded. In the weatherstrip 20 it willalso be seen that the support portion 24 is of a somewhat differentconfiguration than the support portion 14 of the weatherstrip 10. Also,the elastic portion 16 consists of two longitudinally extending webs 26inclined inwardly from the bottom to the top thereof.

The embodiment 30 of FIG. 3 is very similar to that of FIG. 2, exceptthat the contact strip 38 is generally planar having rounded corners.

The weatherstrip 40 of FIG. 4 is similar to the weatherstrip 30 of FIG.3, except that the contact strip 48 is provided with longitudinallyextending ribs on the supper surface thereof.

The weatherstrip 50 of FIG. 5 is similar to the weatherstrip 10 of FIG.1 except that the elastic portion comprises two longitudinally extendingwebs 56.

The embodiment 60 of FIG. 6 is similar to the weatherstrip 30 of FIG. 3,except that one elastic web 66 is taller than the other elastic web 66',and as a result the contact strip 68 is slanted or inclinedtransversely.

The weatherstrip 70 of FIG. 7 is similar to that of FIG. 5, except thatthe support portion 74 is solid. The construction 80 of FIG. 8 combinesfeatures of FIGS. 3 and 5.

The weatherstrip 90 of FIG. 9 is similar to the weatherstrip 40 of FIG.4, except that a different retainer configuration is provided, both thebase portion 92 and the support portion 94 being somewhat different thanthe other illustrated embodiments.

The weatherstrip 100 of FIG. 10 is similar to that of FIG. 3, exceptthat the elastic portion comprises three longitudinally extending webs116. FIG. 10 shows the weatherstrip 100 in a typical use situation,where it is inserted into a suitable slot in the edge of a window ordoor frame 120, so that the rigid contact strip 118 extends towards andin contact with the opposite edge of a door or window 122.

Because the elastic portion underlying the contact strip must in generalhave somewhat different properties than the contact strip in theweatherstrip according to the present invention, these portions arenormally made of different materials. For example, the contact strip 18,28, . . . 118 is desirably formed of polyethylene, e.g. high densitypolyethylene or low density polyethylene, polypropylene or rigid vinylplastic, and the retainer including the base and support portions may beformed of the same material. The elastic portion 16, 26 . . . 116 isdesirably formed of a elastomer such as thermoplastic rubber (TPR),ethylene/vinyl acetate copolymer (EVA) or flexible vinyl.

Weatherstrip material according to the invention may be easily andsimply formed by co-extrusion, a known technique. So that the variousportions will be integral, the different materials used must be somewhatcompatible. Therefore, it is preferred that the elastic portion beformed of TPR when the contact strip is formed of polypropylene, thatthe elastic portion be formed of EVA when the contact strip is formed ofpolyethylene, and that the elastic portion be formed of flexible vinylwhen the contact strip is formed of rigid vinyl.

It will be obvious to those skilled in the art that various otherchanges and modifications may be made without departing from the scopeof the invention and the invention is not to be considered limited towhat is shown in the drawings and described in the specification.

What is claimed is:
 1. An extruded all-polymer weatherstrip having alongitudinally extending base portion of sufficient mechanical strengthto support the weatherstrip in a slot below a surface to be sealed;alongitudinally extending support portion projecting upwardly from saidbase portion and integral and unitary therewith, said support portionbeing sufficiently rigid to substantially retain its shape and positionwhen said weatherstrip is subjected to pressure from the surface to besealed; a longitudinally and transversely extending elastic portionprojecting upwardly from said support portion and integral therewith,said elastic portion being formed of an elastomer or resilient plastic;and a self-supporting, longitudinally extending generally planar contactstrip of thickness on the order of about 25-30 mils for directlycontacting the surface to be sealed, said contact strip being supportedby and integral with the said elastic portion, said contact stripextending transversely and defining the width of said weatherstrip andbeing sufficiently rigid to substantially retain its shape and positionwhen said weatherstrip is subjected to pressure from the surface to besealed.
 2. An extruded all-polymer weatherstrip according to claim 1,wherein said base portion is in the form of an elongated strip.
 3. Aweatherstrip according to claim 1 formed by co-extrusion.
 4. Aweatherstrip according to claim 1 wherein said base portion, saidsupport portion and said contact strip are formed of the same material.5. A weatherstrip according to claim 1 wherein said contact strip isprovided with a plurality of longitudinally extending ribs projectingupwardly therefrom.
 6. A weatherstrip according to claim 1 wherein saidcontact strip is formed of polypropylene and said elastic portion isformed of thermoplastic rubber.
 7. A weatherstrip according to claim 1wherein said contact strip is formed of polyethylene and said elasticportion is formed of ethylene-vinyl acetate copolymer.
 8. An extrudedall-polymer weatherstrip having a longitudinally extending base portionof sufficient mechanical strength to support the weatherstrip in a slotbelow a surface to be sealed;a longitudinally and laterally extendingelastic portion projecting upwardly from said base portion, said elasticportion being formed of an elastomer or resilient plastic; and aself-supporting, longitudinally extending contact strip of thickness onthe order of about 25-30 mils for directly contacting the surface to besealed, said contact strip being supported by and integral with saidelastic portion, said contact strip extending transversely and definingthe width of said weatherstrip and being sufficiently rigid tosubstantially retain its shape and position when said weatherstrip issubjected to pressure from the surface to be sealed.
 9. An extrudedall-polymer weatherstrip according to claim 8, wherein said base portionis in the form of an elongated strip.
 10. A weatherstrip according toclaim 8, formed by co-extrusion.
 11. A weatherstrip according to claim8, wherein said base portion and said contact strip are formed of thesame material.
 12. A weatherstrip according to claim 8 wherein saidcontact strip is provided with a plurality of longitudinally extendingribs projecting upwardly therefrom.
 13. A weatherstrip according toclaim 8 wherein said contact strip is formed of polypropylene and saidelastic portion is formed of thermoplastic rubber.
 14. A weatherstripaccording to claim 8 wherein said contact strip is formed ofpolyethylene and said elastic portion is formed of ethylene-vinylacetate copolymer.
 15. An extruded all-polymer weatherstrip having alongitudinally extending base portion of sufficient mechanical strengthto support the weatherstrip in a slot below a surface to be sealed;alongitudinally and laterally extending elastic portion projectingupwardly from said base portion, said elastic portion being formed of anelastomer or resilient plastic; and a self-supporting, longitudinallyextending contact strip of thickness on the order of about 25-30 milsand having a plurality of longitudinally extending ribs projectingupwardly therefrom, said contact strip being adapted to directly contactthe surface to be sealed, said contact strip being supported by andintegral with said elastic portion, said contact strip extendinglaterally and defining the width of said weatherstrip and overlayingsaid elastic portion across said width, said contact strip beingsufficiently rigid to substantially retain its shape and position whensaid weatherstrip is subjected to pressure from the surface to besealed.